222 REMARKS UPON A STATEMENT 



more difficult to detect the cell-shaped and more rounded globules, 

 although they are quite as certainly present. When the object has 

 not been at all damaged, the cells, and especially the pigment- globules 

 adhering to the outside, exhibit an arrangement like that of the vege- 

 table cells in general, and particularly in the earliest stages in the 

 formation of the leaf, that is, a disposition corresponding to spiral lines 

 projected on the surface in accordance with the strictest rules) 



compared to the cellular tissue of plants, I chose, expressly 



(1. c. 77 . Each of these globules (ganglion-globules), wherever ob- 

 served, has an external, more or less distinct, areolar tissue-like envelope, 

 and contains a parenchymatous mass proper to itself, an independent 

 nucleus or kernel (nucleus oder Kern), which again encloses a 

 second roundish, transparent nucleus) on account of this re- 

 semblance in form, the uniform appellation of the nucleus 

 {Kernes), just as I afterwards described the nucleolus which was 



observed by me. (Repertor. i, 143. In every cell without exception 

 there is a somewhat smaller and more compact nucleus of a round or 

 oval form. It usually occupies the centre of each cell, consists of a 

 minutely granulous substance, but encloses a well-defined, round cor- 

 puscle, which thus forms a sort of second nucleus within it.) In the 



study of the epithelia, prosecuted particularly by Henle and 



myself, there was no want of analogies with vegetable cellular 



tissue, the individuality of the cell-parietes was also distinctly 



demonstrated. (lb. 284. Roundish, hexagonal, flat, aud tolerably 

 thin cells lie (in the external skin of the proteus) close upon one 

 another, disposed in regular arrangement, and always connected 

 together with their lateral edges and angles in mutual correspondence. 

 The interior of these delicate bodies is filled by a granulous or yel- 

 lowish mass, which represents a sort of nucleus. But the separate 

 granules of this nucleus, however closely they may lie together, may 

 be accurately distinguished from one another. With a very strong 

 magnifying power, each one of these granules may be seen to be more 

 transparent in its centre than it is in its periphery. It may then 

 also be most distinctly ascertained, that the somewhat delicate parietes 

 of each cell are perfectly isolated from the central cavity. No trace 

 of granules or fibres can be observed on the walls themselves ; there is 

 merely a clear, transparent, vitreous, and homogeneous mass.) I had 



also remarked that the nuclei {pigment -vesicles) were the parts 



first formed in the pigment of the choroid coat (Entwickelungs- 



geschichte, 194. The following is the mode in which, according to 

 my observations, the stratum of pigment is formed in man, mammalia, 

 and birds ; separate, round, colourless, and transparent corpuscles are 

 first deposited upon the internal surface of the substance they are to 

 cover, in the earliest period (up to the tenth week) these corpuscles in 

 the human subject measure from 0*000355 to 0-000405 Paris inch in 

 diameter. They are the future pigment-corpuscles or pigment- vesicles. 



